The present invention relates generally to a method of reducing metallic debris in a multi-component metallic housing, such as a fuel injector housing, and more particularly to the removal of first and last partial threads in metallic housing components.
Multi-component metallic housings are used for fluid transfer in numerous shapes and sizes, and in a wide variety of arts. In its simplest form, such a multi-component housing includes a first component defining a cavity with internal threads, and a second male component with external threads that threadably attaches to the first component to form a housing. Depending upon the particular application, a fluid is contained within, and often transferred through, the housing. In some applications, it is of critical importance that the fluid be free of particulate debris, such as metallic fragments. One potential source of metallic debris in a multi-component housing is due to the breakage of partial threads when the multi-component housing is assembled.
In one specific example, a fuel injector body is made up of several components assembled to one another by matching internal threads with one component with external threads on another component. As is typical in the art, when the various components of the injector body are machined, the threaded portions include partial beginning and ending threads that are thin and often become brittle after heat treatment. These partial threads are one major source of internal debris in fuel injectors. When the injector is assembled, the mating threads of one component sometimes tend to knock pieces of the thin partial threads free. In some cases, the debris is carried through the injector by fuel flow, which can cause injector plunger seizures and/or plugging of the injector tip orifices. Those skilled in the art will appreciate that both of these situations are extremely undesirable.
The present invention is directed to overcoming one or more of the problems as set forth above.
In responding to this need, the present invention contemplates a method of reducing internal metallic debris in a fuel injector by providing a fuel injector component having a portion with a circular cross section. A set of threads are machined on the portion and includes full threads separated by a beginning partial thread and an ending partial thread. A substantial portion of at least one of the beginning partial thread or the ending partial thread is removed, preferably utilizing a milling process. Thus, internal metallic debris within the fuel injector is reduced since one potential source of such debris is eliminated.
In another embodiment of the present invention, a multi-component metallic housing for a fluid includes a first metallic component defining a cavity that includes a set of internal threads. A second metallic component has an outer surface with a set of external threads mated to the internal threads such that the first component and the second component are attached to one another and define a fluid cavity. The set of internal threads includes a first internal thread and a last internal thread. The set of external threads includes a first external thread and a last external thread. At least one of the first internal thread, the last internal thread, the first external thread or the last external thread is substantially uniform.
One object of the present invention is to reduce internal metallic debris in fuel injectors.
Another object of the present invention is to reduce metallic debris in multi-component metallic housings that are sensitive to loose metallic debris.
Still another object of the present invention is to improve the manufacturing process for fuel injectors and other multi-component metallic housings for fluids.